An impulse tachometer generator which includes a housing featuring a two-part design is known in the
See German Patent No. DE-OS 35 20 288 for a prior art. See German Printer Application 35 30 288 Al for a teaching of such an impulse tachometer generator. In this prior art design, the lower housing part consists of a metallic material, while the upper housing part is manufactured from a synthetic-type material, for example, a suitable plastic. As produced, this lower housing part is cup-shaped, and the upper housing part is designed primarily as a closing member to seal such cup-shaped lower housing part. Such upper housing part includes a cable opening.
As illustrated in the drawing of the above-mentioned reference, the upper housing part extends partially into the lower housing part. This overlapping area between such upper housing part and lower housing part is designed as a support for a pole pin, and a permanent magnet, as well as for a coil which surrounds the pole pin. The front portion of the upper housing part, which faces away from the pole pin, includes a cavity that can be closed with a cover member. Busbars lead into this cavity. Such busbars are connected to the coil, as well as to electric cable leads. The electric cable emerges from the housing and serves to make the necessary electrical connection between the electric component contained within the housing, which electric component is designed as a coil, and an electrical device located external of the housing and also separate from the same.
As previously mentioned, the upper housing part includes a cable lead-through for such electric cable. Such cable lead-through is formed by an opening positioned in the wall of the upper housing part. Located on the wall adjacent the opening, a series of projections are provided which extend to the cable. These projections are designed in a barb-like fashion so that they will catch on the sheathing material surrounding the conductor wire of the electric cable. In this manner, these projections provide some degree of strain relief for such electric cable. However, the strain relief of the cable lead-through, designed in this manner, will have a number of significant disadvantages. For example, it is conceivable that such series of projections, which are molded into the cable lead-through, will not achieve a requisite amount of clamping effect at the electric cable. Insufficient clamping effect may occur due to manufacturing tolerances. With insufficient clamping results, the forces that occur during tensile stress at the electric cable will not be transferred from the cable sheathing material via the series of projections within the cable lead-through onto the housing. Instead, these forces will be transferred onto the cable conductors and/or the electrical component contained in the housing and connected to these electric cables. Obviously, this is not a desirable condition.
One detrimental effect may be that the individual conductors of such electrical cable may break, or the electrical component within the housing may be damaged, thus causing a malfunction of the system in which it forms a part.